The present disclosure relates generally to well logging tools used in subterranean formations and, more particularly, the present disclosure relates to methods and apparatus for measuring electromagnetic propagation resistivity using a drill bit.
To ease the process of drilling into a formation and to improve production yields for desirable formation fluids, the oilfield-services industry has developed processes and tools for measuring properties of the formation during drilling or shortly thereafter, a process called “logging while drilling” (LWD). Integrating logging while drilling not only shortens the time needed to make the well operational, but also allows a drill operator to measure the formation's properties. LWD tools and methods evaluate multiple parameters, such as formation resistivity to determine the types of minerals and/or fluids that comprise the formation. Generally, logging tools and processes involve radiation of energy, such as electromagnetic waves, into the formation to induce energy from the formation. The characteristics of the induced energy reveal properties of the formation. Properties of particular value in the drilling process are the identity, location and relative proportions of minerals and fluids present in the disclosure.
LWD tools incorporate measurement devices into the bottomhole assembly in order to obtain measurements as soon as possible after the well wall is drilled. LWD has thus far been attached to the drill string, for example in specially adapted drill collars located just above the drill bit. Thus, the sensors incorporated into these LWD tools will typically detect formation properties at a depth only after the drill bit drills past that depth. There is a need in the art for improved LWD tools which allow for detection of formation properties before drilling past that depth as well as LWD tools.
While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.